Different grades used for evaluation of disease severity in ulcerative colitis
| Grade 0 | Structural (architectural change) |
| Subgrades | |
| 0.0 | No abnormality |
| 0.1 | Mild abnormality |
| 0.2 | Mild or moderate diffuse or multifocal abnormalities |
| 0.3 | Severe diffuse or multifocal abnormalities |
| Grade 1 | Chronic inflammatory infiltrate |
| Subgrades | |
| 1.0 | No increase |
| 1.1 | Mild but unequivocal increase |
| 1.2 | Moderate increase |
| 1.3 | Marked increase |
| Grade 2 | Lamina propria neutrophils and eosinophils |
| 2A Eosinophils | |
| 2A. 0 | No increase |
| 2A.1 | Mild but unequivocal increase |
| 2A.2 | Moderate increase |
| 2A.3 | Marked increase |
| 2B Neutrophils | |
| 2B. 0 | None |
| 2B.1 | Mild but unequivocal increase |
| 2B.2 | Moderate increase |
| 2B.3 | Marked increase |
| Grade 3 | Neutrophils in epithelium |
| 3.0 | None |
| 3.1 | < 5% crypts involved |
| 3.2 | < 50% crypts involved |
| 3.3 | > 50% crypts involved |
| Grade 4 | Crypt destruction |
| 4.0 | None |
| 4.1 | Probable—local excess of neutrophils in part of crypt |
| 4.2 | Probable—marked attenuation |
| 4.3 | Unequivocal crypt destruction |
| Grade 5 | Erosion or ulceration |
| 5.0 | No erosion, ulceration, or granulation tissue |
| 5.1 | Recovering epithelium+adjacent inflammation |
| 5.2 | Probable erosion—focally stripped |
| 5.3 | Unequivocal erosion |
| 5.4 | Ulcer or granulation tissue |